- In Synchronizer test, test all tx types

- Test L1UserTxs in Synchronizer
- Test Batches in Synchronizer
- Add last_idx in `TABLE batch` in HistoryDB
- Minor updates in til to satisfy blockchain constraints

Add TxTypeTransferToEthAddr&ToBJJ to StateDB & Til
resolves #203, resolves #209

- Node
	- Updated configuration to initialize the interface to all the smart
	  contracts
- Common
	- Moved BlockData and BatchData types to common so that they can be
	  shared among: historydb, til and synchronizer
	- Remove hash.go (it was never used)
	- Remove slot.go (it was never used)
	- Remove smartcontractparams.go (it was never used, and appropriate
	  structs are defined in `eth/`)
	- Comment state / status method until requirements of this method are
	  properly defined, and move it to Synchronizer
- Synchronizer
	- Simplify `Sync` routine to only sync one block per call, and return
	  useful information.
	- Use BlockData and BatchData from common
	- Check that events belong to the expected block hash
	- In L1Batch, query L1UserTxs from HistoryDB
	- Fill ERC20 token information
	- Test AddTokens with test.Client
- HistryDB
	- Use BlockData and BatchData from common
	- Add `GetAllTokens` method
	- Uncomment and update GetL1UserTxs (with corresponding tests)
- Til
	- Rename all instances of RegisterToken to AddToken (to follow the smart
	  contract implementation naming)
	- Use BlockData and BatchData from common
		- Move testL1CoordinatorTxs and testL2Txs to a separate struct
		  from BatchData in Context
	- Start Context with BatchNum = 1 (which the protocol defines to be the
	  first batchNum)
	- In every Batch, set StateRoot and ExitRoot to a non-nil big.Int
	  (zero).
	- In all L1Txs, if LoadAmount is not used, set it to 0; if Amount is not
	  used, set it to 0; so that no *big.Int is nil.
	- In L1UserTx, don't set BatchNum, because when L1UserTxs are created
	  and obtained by the synchronizer, the BatchNum is not known yet (it's
	  a synchronizer job to set it)
	- In L1UserTxs, set `UserOrigin` and set `ToForgeL1TxsNum`.

Update Til with small fixes:
- L2Tx TxID & Type correctness done after Idxs setted
- Added PoolL2Tx signature for Exit type

Common:
- Add common.TxID Marshalers test

Rename Transakcio to Til for a easier usage, also change til.TestContext
to til.Context, and til.NewTestContext to til.NewContext.